1. Field of the Invention
The present invention relates to a punching tool, and more specifically to a punching tool which can reduce punching noise generated during punching processing.
2. Description of the Related Art
Work mounted on a lower die can be punched by moving an upper tool up and down relative to the lower die. During this punching processing, punching noise is inevitably generated. To reduce the generated punching noise, conventionally a damping member such as urethane has been disposed on as tripper plate provided at the lower portion of a punch guide for constituting a part of the upper tool. Or else, the cutting edge of the punch body is formed with a shear angle to reduce the punching noise.
In the conventional method of disposing a damping member such as urethane on the stripper plate provided at the lower portion of the punch guide, there exists a problem in that the work surface is easily scratched because needle-shaped chips generated during punching processing adhere to the damping member. In addition, since the damping member is not durable, there exists another problem in that the life time of the damping member is short and in addition it is rather difficult to mount or bond the damping member on the punch guide. On the other hand, in the conventional method of forming the cutting edge of the punch body with a shear angle, it has been difficult to reduce noise down to a sufficiently low level.